scholarly journals Structural Insights of Transcriptionally Active, Full-Length Androgen Receptor Coactivator Complexes

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A817-A817
Author(s):  
Xinzhe Yu ◽  
Ping Yi

Abstract Steroid hormone receptors activate gene transcription by binding specific DNA sequences and recruiting coactivators to initiate transcription of their target genes. For most nuclear hormone receptors (NRs), the ligand-dependent activation function domain-2 (AF-2), residing in the C-terminal ligand binding domain (LBD), is a primary contributor to the NR transcriptional activity. In contrast to other steroid receptors such as estrogen receptor-α (ERα), the transcriptional activation function of androgen receptor (AR) is thought to be largely dependent on its ligand-independent activation function domain-1 (AF-1) located in its N-terminal domain (NTD). It remains unclear why AR utilizes a different activation function domain from other steroid receptors despite the fact that NRs share similar domain organizations and have a highly conserved DNA binding domain (DBD) and LBD. Here we present cryo-electron microscopic structures of DNA-bound full-length AR and its functional complex structure with its key coactivators, steroid receptor coactivator-3 (SRC-3) and the histone acetyltransferase p300. The structures reveal that androgen-bound full-length AR dimerization follows a unique head-to-head and tail-to-tail manner with all of the domains involved. The DBD and LBD are located at the center of the dimer interface. The NTDs wrap around the LBDs through their unique intra- and inter-molecular N- and C-terminal interactions and connect to each other. We observe that unlike ERα, AR binds a single SRC-3 molecule along with a single p300 molecule. The AR NTD appears to be the primary site for recruitment of both coactivators. The N-terminal region of SRC-3, rather than its receptor interaction domain, is important for this interaction. The structures presented here highlight the importance of the AR NTD for its transcriptional functions and provide a structural basis for understanding the assembly of the AR:coactivator complex and its domain contributions to transcriptional regulation.

2003 ◽  
Vol 23 (5) ◽  
pp. 1674-1687 ◽  
Author(s):  
Liang-Nian Song ◽  
Roger Herrell ◽  
Stephen Byers ◽  
Salimuddin Shah ◽  
Elizabeth M. Wilson ◽  
...  

ABSTRACT β-Catenin is a multifunctional molecule that is activated by signaling through WNT receptors. β-Catenin can also enhance the transcriptional activity of some steroid hormone receptors such as the androgen receptor and retinoic acid receptor α. Androgens can affect nuclear translocation of β-catenin and influence its subcellular distribution. Using mammalian two-hybrid binding assays, analysis of reporter gene transcription, and coimmunoprecipitation, we now show that β-catenin binds to the androgen receptor ligand-binding domain (LBD) and modulates the transcriptional effects of TIF2 and the androgen receptor N-terminal domain (NTD). In functional assays, β-catenin bound to androgen receptor only in the presence of ligand agonists, not antagonists. β-Catenin binding to the androgen receptor LBD was independent of and cooperative with the androgen receptor NTD and the p160 coactivator TIF2, both of which bind to the activation function 2 (AF-2) region of the androgen receptor. Different mutations of androgen receptor helix 3 amino acids disrupted binding of androgen receptor NTD and β-catenin. β-Catenin, androgen receptor NTD, and TIF2 binding to the androgen receptor LBD were affected similarly by a subset of helix 12 mutations, but disruption of two sites on helix 12 affected only binding of β-catenin and not of TIF2 or the androgen receptor NTD. Mutational disruption of each of five LXXLL peptide motifs in the β-catenin armadillo repeats did not disrupt either binding to androgen receptor or transcriptional coactivation. ICAT, an inhibitor of T-cell factor 4 (TCF-4), and E-cadherin binding to β-catenin also blocked binding of the androgen receptor LBD. We also demonstrated cross talk between the WNT and androgen receptor signaling pathways because excess androgen receptor could interfere with WNT signaling and excess TCF-4 inhibited the interaction of β-catenin and androgen receptor. Taken together, the data show that β-catenin can bind to the androgen receptor LBD and modulate the effects of the androgen receptor NTD and TIF2 on transcription.


2005 ◽  
Vol 25 (4) ◽  
pp. 1238-1257 ◽  
Author(s):  
Suxia Bai ◽  
Bin He ◽  
Elizabeth M. Wilson

ABSTRACT Gene activation by steroid hormone receptors involves the recruitment of the steroid receptor coactivator (SRC)/p160 coactivator LXXLL motifs to activation function 2 (AF2) in the ligand binding domain. For the androgen receptor (AR), AF2 also serves as the interaction site for the AR NH2-terminal FXXLF motif in the androgen-dependent NH2-terminal and carboxyl-terminal (N/C) interaction. The relative importance of the AR AF2 site has been unclear, since the AR FXXLF motif interferes with coactivator recruitment by competitive inhibition of LXXLL motif binding. In this report, we identified the X chromosome-linked melanoma antigen gene product MAGE-11 as an AR coregulator that specifically binds the AR NH2-terminal FXXLF motif. Binding of MAGE-11 to the AR FXXLF α-helical region stabilizes the ligand-free AR and, in the presence of an agonist, increases exposure of AF2 to the recruitment and activation by the SRC/p160 coactivators. Intracellular association between AR and MAGE-11 is supported by their coimmunoprecipitation and colocalization in the absence and presence of hormone and by competitive inhibition of the N/C interaction. AR transactivation increases in response to MAGE-11 and the SRC/p160 coactivators through mechanisms that include but are not limited to the AF2 site. MAGE-11 is expressed in androgen-dependent tissues and in prostate cancer cell lines. The results suggest MAGE-11 is a unique AR coregulator that increases AR activity by modulating the AR interdomain interaction.


2020 ◽  
Author(s):  
Azhagiya Singam Ettayapuram Ramaprasad ◽  
Phum Tachachartvanich ◽  
Denis Fourches ◽  
Anatoly Soshilov ◽  
Jennifer C.Y. Hsieh ◽  
...  

Perfluoroalkyl and Polyfluoroalkyl Substances (PFASs) pose a substantial threat as endocrine disruptors, and thus early identification of those that may interact with steroid hormone receptors, such as the androgen receptor (AR), is critical. In this study we screened 5,206 PFASs from the CompTox database against the different binding sites on the AR using both molecular docking and machine learning techniques. We developed support vector machine models trained on Tox21 data to classify the active and inactive PFASs for AR using different chemical fingerprints as features. The maximum accuracy was 95.01% and Matthew’s correlation coefficient (MCC) was 0.76 respectively, based on MACCS fingerprints (MACCSFP). The combination of docking-based screening and machine learning models identified 29 PFASs that have strong potential for activity against the AR and should be considered priority chemicals for biological toxicity testing.


2001 ◽  
Vol 361 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Guy VERRIJDT ◽  
Annemie HAELENS ◽  
Erik SCHOENMAKERS ◽  
Wilfried ROMBAUTS ◽  
Frank CLAESSENS

We performed a comparative analysis of the effect of high-mobility group box protein 1 (HMGB1) on DNA binding by the DNA-binding domains (DBDs) of the androgen, glucocorticoid, progesterone and mineralocorticoid receptors. The affinity of the DBDs of the different receptors for the tyrosine aminotransferase glucocorticoid response element, a classical high-affinity binding element, was augmented up to 7-fold by HMGB1. We found no major differences in the effects of HMGB1 on DNA binding between the different steroid hormone receptors. In transient transfection assays, however, HMGB1 significantly enhances the activity of the glucocorticoid and progesterone receptors but not the androgen or mineralocorticoid receptor. We also investigated the effect of HMGB1 on the binding of the androgen receptor DBD to a subclass of directly repeated response elements that is recognized exclusively by the androgen receptor and not by the glucocorticoid, progesterone or mineralocorticoid receptor. Surprisingly, a deletion of 26 amino acid residues from the C-terminal extension of the androgen receptor DBD does not influence DNA binding but destroys its sensitivity to HMGB1. Deletion of the corresponding fragment in the DBDs of the glucocorticoid, progesterone and mineralocorticoid receptor destroyed their DNA binding. This 26-residue fragment is therefore essential for the influence of HMGB1 on DNA recognition by all steroid hormone receptors that were tested. However, it is dispensable for DNA binding by the androgen receptor.


2016 ◽  
Vol 14 (1) ◽  
pp. nrs.14001 ◽  
Author(s):  
Yingfeng Zheng ◽  
Leigh C. Murphy

Cell cycle progression is tightly controlled by several kinase families including Cyclin-Dependent Kinases, Polo-Like Kinases, and Aurora Kinases. A large amount of data show that steroid hormone receptors and various components of the cell cycle, including cell cycle regulated kinases, interact, and this often results in altered transcriptional activity of the receptor. Furthermore, steroid hormones, through their receptors, can also regulate the transcriptional expression of genes that are required for cell cycle regulation. However, emerging data suggest that steroid hormone receptors may have roles in cell cycle progression independent of their transcriptional activity. The following is a review of how steroid receptors and their coregulators can regulate or be regulated by the cell cycle machinery, with a particular focus on roles independent of transcription in G2/M.


2005 ◽  
Vol 34 (2) ◽  
pp. 517-534 ◽  
Author(s):  
S Hombach-Klonisch ◽  
A Kehlen ◽  
P A Fowler ◽  
B Huppertz ◽  
J F Jugert ◽  
...  

Information on the regulation of steroid hormone receptors and their distinct functions within the human endometrial epithelium is largely unavailable. We have immortalized human primary endometrial epithelial cells (EECs) isolated from a normal proliferative phase endometrium by stably transfecting the catalytic subunit (hTERT) of the human telomerase complex and cultured these hTERT-EECs now for over 350 population doublings. Active hTERT was detected in hTERT-EECs employing the telomerase repeat amplification assay protocol. hTERT-EECs revealed a polarized, non-invasive epithelial phenotype with apical microvilli and production of a basal lamina when grown on a three-dimensional collagen–fibroblast lattice. Employing atomic force microscopy, living hTERT-EECs were shown to produce extracellular matrix (ECM) components and ECM secretion was modified by estrogen and progesterone (P4). hTERT-EECs expressed inducible and functional endogenous estrogen receptor-alpha (ER-alpha) as demonstrated by estrogen response element reporter assays and induction of P4 receptor (PR). P4 treatment down-regulated PR expression, induced MUC-1 gene activity and resulted in increased ER-beta transcriptional activity. Gene activities of cytokines and their receptors interleukin (IL)-6, leukemia inhibitory factor (LIF), IL-11 and IL-6 receptor (IL6-R), LIF receptor and gp130 relevant to implantation revealed a 17 beta-estradiol (E2)-mediated up-regulation of IL-6 and an E2- and P4-mediated up-regulation of IL6-R in hTERT-EECs. Thus, hTERT-EECs may be regarded as a novel in vitro model to investigate the role of human EECs in steroid hormone-dependent normal physiology and pathologies, including implantation failure, endometriosis and endometrial cancer.


1993 ◽  
Vol 13 (12) ◽  
pp. 7850-7858
Author(s):  
F Kaspar ◽  
H Klocker ◽  
A Denninger ◽  
A C Cato

Reifenstein syndrome is an eponymic term that describes partial androgen-insensitive disorders. Androgen receptor isolated from five patients with this syndrome contains a specific mutation in the DNA binding domain of the receptor. This mutation converts an alanine to a threonine at position 596 next to the zinc catenation site at the second finger. The threonine 596 mutant receptor mediated normal androgen response at promoters with closely positioned multiple regulatory elements for the androgen receptor and other transcription factors. Promoters with single isolated androgen response elements were not transactivated by the mutant receptor. In in vitro receptor-DNA binding studies, interaction with DNA by the mutant receptor was achieved only in the presence of an anti-androgen receptor antibody. Exchanging alanine 596 in the wild-type androgen receptor with serine or valine produced mutants with properties indistinguishable from those of the naturally occurring threonine 596 mutant receptor. These results indicate that an alanine residue at position 596 contributes important structural and functional activities to the androgen receptor. In the androgen receptor from the patients with Reifenstein syndrome, in which this alanine is converted to a threonine, wild-type receptor properties can be restored by exchanging an additional threonine at position 602 to an alanine. An alanine residue at position 596 or 602 in the DNA binding domain of the androgen receptor is therefore important for the full function of this receptor. In all steroid receptors that bind the core sequence AGAACANNNTGTTCT, an alanine residue is also present at a position equivalent to alanine 596 in the androgen receptor.


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